Demonstration of laser and modulator integration on a photonic chip

One of the main objectives of the IRT Nanoelec Silicon Photonics program is to integrate multiple optical functions onto a single circuit. Specifically, the goal is to integrate a laser source and modulator to create a high-speed transmitter.

An initial demonstrator based on the research of Thomas Ferrotti, a PhD candidate conducting research at CIFRE, was completed under the IRT Nanoelec Photonics program. A DFB laser source obtained using direct bonding of III–V vignettes on Si was combined with a Mach-Zehnder-type silicon modulator for data transmission at speeds of 25 Gbits/s within the o frequency band (1310 nm).

The silicon circuit and bonding of the III–V vignettes were done on a 200 mm wafer; the final steps of the process were on 100 mm wafers. Transmission tests (over 10 km of fiber optic cable)  were successful. These tests, combined with the production of receiver modules at 25 Gbits/s, demonstrate the validity of this type of integration for optical links for future generations of data centers.

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Electro-optical modulation at 25 Gbits/s using a 4 mm
modulator with voltage of 2.5 Vpp on each arm
Test bench – Research by Thomas Ferrotti,
PhD candidate at CIFRE/Leti-ST



Modulator length: 4 mm

Speed: 25 Gbits/s

Voltage on each arm: 2.5 Vpp

Extinction rate: 4.7 dB